Triplephase93
Member
Is there any realistic chance that the warm nose doesn’t get as far North as modeled and places like HSV get more ice/sleet rather than rain?
No the warm nose is inevitable. It might be delayed but won’t be denied
Is there any realistic chance that the warm nose doesn’t get as far North as modeled and places like HSV get more ice/sleet rather than rain?
Thanks for the input!No the warm nose is inevitable. It might be delayed but won’t be denied
For Raleigh Google has about 0.5-0.6” precip in very cold temps for the overrunning part. Another .2” comes after as probably freezing rain. It’s a cold model…hoping the initial overrunning is half sleet and half frzn. Would be a nice event but not catastrophic, I hope. Roads would be an ice skating rink and would still be power outages, just not worst case
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| Model | Precip Onset/Duration | QPF | P-Type Notes | General Notes/Trends |
| ECMWF (06z, 1/23) | 00z-03z Sunday/~24 hours | 1.2-2.5", mostly in the 1.2-1.5" zone | North of I-40, 12ish hours of sleet before ZR kicks in. Along and south of I-85, starting as ZR. Probably not to be trusted on CAD depth | Drying trend noted. Still plenty of QPF. Likely not enough to make a massive difference further south but the more QPF you use on sleet in the NC Foothills, the better |
| GFS (06z, 1/23) | 21z Sat-00z Sun/~27 hours | 1.5-3", mostly 1.5-2.2" | Northwest of I-85, starting as sleet/snow. Roughly half/half sleet/snow then ZR. Along and southwest of I-85 maybe more like 25/75 sleet/ZR. | Starting to tick drier, has been one of the wettest models. Again, may not make a huge difference. Hasn't wavered much lately. |
| RDPS (06z, 1/23) | 23z Sat-02z Sun/~24-26 hours | 1.1-2.7", mostly 1-2" | Similar splits. I-40 north is sleet for longer, I-85 ZR a little before halfway | Maybe a smidge wetter, but splitting hairs. Large rain shadow noted just west of French Broad Valley |
| EC AIFS (06z, 1/23) | 00z-03z Sun/~24-27 hours | 0.8-1.5", mostly 0.8-1.2" | Again, looks similar to other models. North of 40 hangs onto sleet until perhaps 15z, I-85 only until 06z-09z | Has been the driest and while 06z was a bit drier vs 00z, the general trend hasn't moved a huge amount in the last 5 runs. Would think this amount of precip would still cause plenty of damage in the Upstate, far SWNC, and NE GA given less sleet. |
| NAM 12k (06z, 1/23) | 03z Sun, 21-24 hours | 0.7-1.2" | Similar to other models based off soundings. Looks most ZR-y for 85 corridor in Upstate with 18 hours of ZR | Most annoying model so far with dry slots in the NC Foothills. I can't quite fully discount this but would love to for forecast simplicity's sake. If it continues drier into tonight's runs it gets more weight. Would love the HREF to be in range. |
Good to note that this estimates radial accrual and the NWS forecasts FLAT accrual. So if you see a big difference between the FRAM estimates and the NWS maps, that is the reasonHere are the FRAM totals from the NWS blend of models. Many of us would be happy with these accumulations. The NWS in Raleigh has been leaning heavily on this model.View attachment 187932
Once again, this is meant for the Upstate of SC, NC Foothills (west of I-77), and NC Mountains
Model Precip Onset/Duration QPF P-Type Notes General Notes/Trends ECMWF (06z, 1/23) 00z-03z Sunday/~24 hours 1.2-2.5", mostly in the 1.2-1.5" zone North of I-40, 12ish hours of sleet before ZR kicks in. Along and south of I-85, starting as ZR. Probably not to be trusted on CAD depth Drying trend noted. Still plenty of QPF. Likely not enough to make a massive difference further south but the more QPF you use on sleet in the NC Foothills, the better GFS (06z, 1/23) 21z Sat-00z Sun/~27 hours 1.5-3", mostly 1.5-2.2" Northwest of I-85, starting as sleet/snow. Roughly half/half sleet/snow then ZR. Along and southwest of I-85 maybe more like 25/75 sleet/ZR. Starting to tick drier, has been one of the wettest models. Again, may not make a huge difference. Hasn't wavered much lately. RDPS (06z, 1/23) 23z Sat-02z Sun/~24-26 hours 1.1-2.7", mostly 1-2" Similar splits. I-40 north is sleet for longer, I-85 ZR a little before halfway Maybe a smidge wetter, but splitting hairs. Large rain shadow noted just west of French Broad Valley EC AIFS (06z, 1/23) 00z-03z Sun/~24-27 hours 0.8-1.5", mostly 0.8-1.2" Again, looks similar to other models. North of 40 hangs onto sleet until perhaps 15z, I-85 only until 06z-09z Has been the driest and while 06z was a bit drier vs 00z, the general trend hasn't moved a huge amount in the last 5 runs. Would think this amount of precip would still cause plenty of damage in the Upstate, far SWNC, and NE GA given less sleet. NAM 12k (06z, 1/23) 03z Sun, 21-24 hours 0.7-1.2" Similar to other models based off soundings. Looks most ZR-y for 85 corridor in Upstate with 18 hours of ZR Most annoying model so far with dry slots in the NC Foothills. I can't quite fully discount this but would love to for forecast simplicity's sake. If it continues drier into tonight's runs it gets more weight. Would love the HREF to be in range.
Other notes: EPS a good bit wetter in UpSC/WNC vs AIFS ENS. Still stand by the opinion that lighter QPF may still see freezing drizzle/light rain at a consistent rate for the duration. NAM erodes the wedge into the low 30s south of I-40 sunday night. RGEM does not but may be too cold? Conventional wisdom from prior forecasts tells me this wedge should hold and the NAM is still fairly far out in its range for that portion of the event. Will it matter much? I don't really think so, in fact gusty winds right after a ZR event sounds pretty bad to me. There may have been too much opining on this topic for the deeper CAD regions when we should be focusing on the 24 hours of frozen precip IMO. I am guilty of it as well. Matters more for GA/southern Upstate folks.
All in all, the SC escarpment and southern NC escarpment, as well as parts of far SWNC and a good chunk of the western Upstate/NE GA will be at the highest ZR risk IMO. That little bit extra elevation is going to result in less sleet, with some places potentially only seeing a couple hours of sleet before ZR takes over. Consistent orographic upslope flow in the south facing mountains/escarpment + flow over CAD dome should mean QPF won't be a problem there. I don't really think it will be a problem anywhere in this region but the NAM makes me stop and wonder for a moment.
Favoring more sleet along and north of I-40, but while we always say CAD is underestimated, we also say warm noses are underestimated as well. Not everything can be underestimated, right? The transition zone between major/moderate ZR seems to be somewhere near the state line of NC/SC to me, with some wiggle room to go further north or south. I am personally not as bullish on the ZR potential in the NC Foothills as the GSP accumulation maps, although even half of what is being forecast there would still cause problems after all the sleet, and I am just a new kid on the block opining on a weather forum. Don't take me for your official guidance, please!
Lastly I am holding out hope for sleet to win out for longer than anticipated here in the Upstate. I don't think it will west of Greenville and south of I-85, but I hope it will. I hope this one busts and the Upstate remembers the crippling ice storm that could have been.
Yep. And if the driest models verify. That .2-.4 of liquid they show will all accrete, since it’s falling as a steady drizzle/light rain. For places like Atlanta, Athens, Augusta, Columbia.Put me down as someone who thinks the freezing drizzle side of things will overperform. That moist flow on top of that wedge. Going to be one of those nights where it’s raining even when the radar doesn’t show anything
Good to see the RGEM and RGEM growing the precip min in eastern NC...could save a lot of folks from power outages.
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It follows the theme of the AI models of growing the precip min in eastern NC. Would be nice.Wow, that's a huge difference, and NAM just erases the storm for a huge chunk of the Carolinas.
Great info man and I didn't realize (or had forgot most likely) that NWS forecast flat ice accrual. Also seems on average takes close to an inch of qpf to get enough ice accrual to really start stressing power lines (.25 or more). Seems confusing to the public though, if official forecast is for .75" and that translates to basically .25 radial, borderline issue.Here are some examples of radial ice measurements with liquid totals included, for reference.
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For sleet yeahEverywhere I look on models seems like the triad seems to be in a great spot.
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For sleet yeah
Hour 36:
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Column crasher? We can only hope it's more sleet than ZR at this point as we are headed for a historic ice storm. Ne Ga to you look to be the worst hit on modeling and I sit right in the middle....sighDews coming in even colder on the 12z hrrrr. This wedge is gonna overperform.
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-12 dew points I don't think I've ever seen that before. Until I see a -19 dew point around the Triad
That snow line keeps creeping south twenty miles or so it seems every run. Two more ticks and we’re looking good in my area
Over running events are notorious for this. Throw in a CAD, that in my opinion is not being modeled all that well and yeah, surprise!For what it's worth....the NAM and others on yesterday's runs should it pretty dry for west GA area this morning and we've been under a nice misting rain must this morning. Who knows if that translates downstream tomorrow night when it does have qpf but lower side and if that's under done especially thru GA